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Involvement of ATP--sensitive potassium channels in proliferation and differentiation of rat preadipocytes

Wang Yaohui, Zheng Haiyan, Qin Nalin, Yu Shangbin, Liu Shengyuan

Department of Pathophysiology, Tongji Medical College, Huazhong University of Science and Technology.Wuhan 430030,Hubei；China

Abstract

This paper was aimed to investigate the effects of ATP-sensitive potassium channels on the proliferation and differentiation of rat preadipocytes. We examined the expression of sulphonylurea receptor 2 (SUR2) mRNA in preadipocytes and adipocytes obtained by inducing for 5 d and the effects of the inhibitor (glibenclamide) and opener (diazoxide) of ATP-sensitive potassium channels on the expression of SUR2 mRNA in preadipocytes by real-time PCR. Preadipocyte proliferation and cell cycle were measured by MTT spectrophotometry and flow cytometer. The content of intracellular lipid was measured by oil red O staining, cell diameter was determined by Image-Pro Plus 5.0 software and the expression of peroxisome proliferator-activated receptor-#gamma#(PPAR-#gamma#) mRNA was estimated by RT-PCR. SUR2 mRNA was expressed in both preadipocytes and adipocytes obtained by inducing for 5 d, and the expression in adipocytes was obviously higher than that in preadipocytes. Glibenclamide inhibited the expression of SUR2 mRNA in preadipocyte, promoted preadipocyte proliferation in a dose-dependent manner, increased the cell percentages in G_(2)/M + S phase,increased lipid content, augmented adipocyte diameter, and promoted the expression of PPAR-#gamma# mRNA. But the actions of diazoxide were contrary to those of glibenclamide. These results suggest that ATP-sensitive potassium channels regulate the proliferation and differentiation of preadipocytes, and PPAR-#gamma# is probably involved in the effect of ATP-sensitive potassium channels.

Key words: Rat;Potassium channels;sulphonylurea receptor;adipocyte;obesity;Cell proliferation;cell differentiation

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Citing This Article：

Wang Yaohui, Zheng Haiyan, Qin Nalin, Yu Shangbin, Liu Shengyuan. Involvement of ATP--sensitive potassium channels in proliferation and differentiation of rat preadipocytes. Acta Physiol Sin 2007; 59 (1): 8-12 (in Chinese with English abstract).